1. Field of the Invention:
The present invention relates to suture collars for use in ligating veins with inserted electrodes, to firmly tie the vein to the electrode, and a method of installation.
2. Description of the Prior Art:
It is well known that damage can occur to both polyurethane and silicone electrode leads if a suture is tiqhtly tied around the body of the electrode lead. To avoid damage to the lead body, manufacturers have developed a variety of suture collars. There are three basic types of suture collars available on the market. The simplest, which is depicted in FIGS. 1A and 1B, is a silicone tube (depicted by the letter "a" in the Figures) which fits over electrode lead body "b" and is partially inserted into vein "c" at the lead entry site "d". Sutures "e" are then tied over the vein, sleeve and lead body. Although not shown, these collars generally have a longitudinal slit to facilitate installation over the lead body.
A slightly more sophisticated collar has a sleeve with a butterfly collar portion which can be anchored to the surrounding tissue. As depicted in FIGS. 2A and 2B, collar "f" includes butterfly portion "g" with wings "h", "i" which can be folded around vein "c" (FIG. 2B) and tied by suture "j".
The third type of collar is a sleeve with a groove formed in the collar exterior surface. As is depicted in FIG. 3, a collar "k" of this type sits on the vein and is anchored by tying suture "l" around groove "m" and vein "c".
Problems with conventional suture collars stem from the need to be able to slide the collar along the electrode lead into place at the vein entry site while still providing an anchor for the electrode lead. The bore of the collar typically is made only slightly larger than the outer diameter of the lead. However, small variations in either the collar inside diameter or the lead outside diameter can result in a situation where excessive interference is present and undue force is required to slide the collar, leading to possible damage to the lead, or a situation where the collar is too loose and no firm anchor is provided. Also, in either case the sutures can cut the vein if too much tension is applied, especially in the latter situation if the surgeon attempts to constrict the collar by tightening the sutures.